Expression of proteoglycan decorin in neural retina.

PURPOSE To identify the expression of chondroitin/dermatan sulfate proteoglycan decorin in retina and to elucidate its changes during development and ischemia-reperfusion. METHODS Expression of decorin in rat retina was investigated by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Distributional changes during development and transient ischemia in model eyes also were investigated by immunohistochemical experiments. RESULTS Gene expression of decorin core protein was identified in rat retina by RT-PCR. Decorin immunoreactivities were shown throughout the retina, especially in the ganglion cell layer. In developing rat retinas, at embryonic stages (embryonic day 16), decorin was distributed uniformly throughout the retina. As retina matured, the intensity of decorin immunostaining in retinal inner layers and retinal pigment epithelium increased. Furthermore, in experimental transient retinal ischemia, after transient downregulation of the decorin core protein gene between 24 and 48 hours after the ischemia, recovered (or increased) expression was shown by semiquantitative RT-PCR experiments. Immunohistochemical studies revealed strong decorin immunoreactivities in the damaged inner layers 1 week later. CONCLUSIONS The expression of decorin was identified in adult and developing rat retina. The distributional changes of decorin during the retinal development suggest that this proteoglycan may play a role in the differentiation of retinal ganglion cells. Moreover, in rat ischemia-reperfusion models, the alterations in gene expression and immunohistochemical localization showed the contribution of this proteoglycan to the damage and repair processes in diseased retina.